[PATCH v5] target/riscv: fix H extension TVM trap

[Yi Chen]

- Trap satp/hgatp accesses from HS-mode when MSTATUS.TVM is enabled.
- Trap satp accesses from VS-mode when HSTATUS.VTVM is enabled.
- Raise RISCV_EXCP_ILLEGAL_INST when U-mode executes SFENCE.VMA/SINVAL.VMA.
- Raise RISCV_EXCP_VIRT_INSTRUCTION_FAULT when VU-mode executes
  SFENCE.VMA/SINVAL.VMA or VS-mode executes SFENCE.VMA/SINVAL.VMA with
  HSTATUS.VTVM enabled.
- Raise RISCV_EXCP_VIRT_INSTRUCTION_FAULT when VU-mode executes
  HFENCE.GVMA/HFENCE.VVMA/HINVAL.GVMA/HINVAL.VVMA.

Signed-off-by: Yi Chen <chenyi2000@zju.edu.cn>
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
---
Rebase the patch on https://github.com/alistair23/qemu/tree/riscv-to-apply.next
Add "Reviewed-by: LIU Zhiwei"
 target/riscv/csr.c       | 56 +++++++++++++++++++++++++---------------
 target/riscv/op_helper.c | 12 ++++-----
 2 files changed, 41 insertions(+), 27 deletions(-)

diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index e0b871f6dc..d6669d8524 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -449,6 +449,30 @@ static RISCVException sstc_32(CPURISCVState *env, int 
csrno)
     return sstc(env, csrno);
 }
 
+static RISCVException satp(CPURISCVState *env, int csrno)
+{
+    if (env->priv == PRV_S && !env->virt_enabled &&
+        get_field(env->mstatus, MSTATUS_TVM)) {
+        return RISCV_EXCP_ILLEGAL_INST;
+    }
+    if (env->priv == PRV_S && env->virt_enabled &&
+        get_field(env->hstatus, HSTATUS_VTVM)) {
+        return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
+    }
+
+    return smode(env, csrno);
+}
+
+static RISCVException hgatp(CPURISCVState *env, int csrno)
+{
+    if (env->priv == PRV_S && !env->virt_enabled &&
+        get_field(env->mstatus, MSTATUS_TVM)) {
+        return RISCV_EXCP_ILLEGAL_INST;
+    }
+
+    return hmode(env, csrno);
+}
+
 /* Checks if PointerMasking registers could be accessed */
 static RISCVException pointer_masking(CPURISCVState *env, int csrno)
 {
@@ -2647,13 +2671,7 @@ static RISCVException read_satp(CPURISCVState *env, int 
csrno,
         *val = 0;
         return RISCV_EXCP_NONE;
     }
-
-    if (env->priv == PRV_S && get_field(env->mstatus, MSTATUS_TVM)) {
-        return RISCV_EXCP_ILLEGAL_INST;
-    } else {
-        *val = env->satp;
-    }
-
+    *val = env->satp;
     return RISCV_EXCP_NONE;
 }
 
@@ -2676,18 +2694,14 @@ static RISCVException write_satp(CPURISCVState *env, 
int csrno,
     }
 
     if (vm && mask) {
-        if (env->priv == PRV_S && get_field(env->mstatus, MSTATUS_TVM)) {
-            return RISCV_EXCP_ILLEGAL_INST;
-        } else {
-            /*
-             * The ISA defines SATP.MODE=Bare as "no translation", but we still
-             * pass these through QEMU's TLB emulation as it improves
-             * performance.  Flushing the TLB on SATP writes with paging
-             * enabled avoids leaking those invalid cached mappings.
-             */
-            tlb_flush(env_cpu(env));
-            env->satp = val;
-        }
+        /*
+         * The ISA defines SATP.MODE=Bare as "no translation", but we still
+         * pass these through QEMU's TLB emulation as it improves
+         * performance.  Flushing the TLB on SATP writes with paging
+         * enabled avoids leaking those invalid cached mappings.
+         */
+        tlb_flush(env_cpu(env));
+        env->satp = val;
     }
     return RISCV_EXCP_NONE;
 }
@@ -4183,7 +4197,7 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
                          .min_priv_ver = PRIV_VERSION_1_12_0 },
 
     /* Supervisor Protection and Translation */
-    [CSR_SATP]     = { "satp",     smode, read_satp,     write_satp     },
+    [CSR_SATP]     = { "satp",     satp, read_satp,     write_satp     },
 
     /* Supervisor-Level Window to Indirectly Accessed Registers (AIA) */
     [CSR_SISELECT]   = { "siselect",   aia_smode, NULL, NULL, rmw_xiselect },
@@ -4220,7 +4234,7 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
                           .min_priv_ver = PRIV_VERSION_1_12_0                },
     [CSR_HGEIP]       = { "hgeip",       hmode,   read_hgeip,
                           .min_priv_ver = PRIV_VERSION_1_12_0                },
-    [CSR_HGATP]       = { "hgatp",       hmode,   read_hgatp,   write_hgatp,
+    [CSR_HGATP]       = { "hgatp",       hgatp,   read_hgatp,   write_hgatp,
                           .min_priv_ver = PRIV_VERSION_1_12_0                },
     [CSR_HTIMEDELTA]  = { "htimedelta",  hmode,   read_htimedelta,
                           write_htimedelta,
diff --git a/target/riscv/op_helper.c b/target/riscv/op_helper.c
index ec9a384772..7cbe13db3f 100644
--- a/target/riscv/op_helper.c
+++ b/target/riscv/op_helper.c
@@ -380,12 +380,12 @@ void helper_wfi(CPURISCVState *env)
 void helper_tlb_flush(CPURISCVState *env)
 {
     CPUState *cs = env_cpu(env);
-    if (!(env->priv >= PRV_S) ||
-        (env->priv == PRV_S &&
-         get_field(env->mstatus, MSTATUS_TVM))) {
+    if (!env->virt_enabled &&
+        (env->priv == PRV_U ||
+         (env->priv == PRV_S && get_field(env->mstatus, MSTATUS_TVM)))) {
         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
-    } else if (riscv_has_ext(env, RVH) && env->virt_enabled &&
-               get_field(env->hstatus, HSTATUS_VTVM)) {
+    } else if (env->virt_enabled &&
+               (env->priv == PRV_U || get_field(env->hstatus, HSTATUS_VTVM))) {
         riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
     } else {
         tlb_flush(cs);
@@ -402,7 +402,7 @@ void helper_hyp_tlb_flush(CPURISCVState *env)
 {
     CPUState *cs = env_cpu(env);
 
-    if (env->priv == PRV_S && env->virt_enabled) {
+    if (env->virt_enabled) {
         riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
     }
 
-- 
2.40.0